Level 6 on his scale is "practical atheist".
Did you notice that Dawkins's own scale places "knowing" at the top and bottom? His scale already demonstrates that separating knowledge and belief is playing with semantics. The pre-20th century understanding of the mind would hold that it was possible to attain absolute knowledge of a subject...any subject, but the gathering of evidence from neuroscience and cognitive psychology shows otherwise. There is nothing external or internal (even our understanding of our own mind is a construction of brain function) that can completely rule out error. We have many beliefs that we can have confidence in because they are verifiable and repeatable from other lines of evidence, and agreed to by others (that may be our most important confirmation), but there is no such thing as knowing in an absolute sense....or certainly not one that can be separated or distinguished from belief.
So, getting back to Dawkins's scale: #1 is the absolute believer as typified by Carl Jung, who stated something about 'not believing in God, but knowing that God exists.' While #7 is "I know there is no God, with the same conviction as Jung knows there is one." #6 is "very low probability, but short of zero." Now, in all honesty, which category does someone like Richard Dawkins - who has sidelined his work in biology to try to create and lead an atheist movement really belong in? I would say that if he is really honest with his readers (and to himself for that matter) it would be #7, because he writes and speaks with the conviction that gods and all supernatural beliefs are delusional and harmful, with the same conviction that Carl Jung believed that God exists.
I don't think anyone has suggested that all agnostics are atheists, but I think it's reasonable to say that many are.
IMO, their resistance to the term has more to do with the baggage our culture attaches to the word "atheist" than the strict definition of the term not applying to them.
Well, how about someone like Soren Kierkegaard? He would be classified as a Christian agnostic on such a dual scale, since he strongly believed in God, but also strongly believed that faith was a leap beyond reason into the absurd.
But someone who writes about agnosticism today, like the previously mentioned Mark Vernon, would have remained an Anglican priest if his faith hadn't been replaced by doubt and uncertainty. A couple of years ago,
he wrote a piece for the Guardian UK describing three commonly used, general categories of agnostics. The common thread is that they have a high degree of uncertainty at their base, so the Carl Jungs and Richard Dawkins would not fit in any of the agnostic categories.